The present invention relates generally to optical parametric oscillators, and more particularly, to an improved optical parametric oscillator having excellent beam quality.
Prior art for an optical parametric oscillator includes a flat-flat resonator (using two flat mirrors disposed on opposite sides of a KTP crystal used as a nonlinear medium), or an unstable resonator with a diagonal coupling mirror inside the resonator. Such optical parametric oscillators are disclosed in a paper by Mark Bowers, et al., Paper CThY3, Conference on Lasers and Electro-Optics (CLEO), Baltimore, Md. p.455 (1997).
The flat-flat resonator has relatively poor output (signal) beam quality due to its limited mode discrimination. The diagonal mirror coupling scheme proposed in the Bowers, et al. paper is relatively complex, and has not been demonstrated.
Accordingly, it is an objective of the present invention to provide for an improved optical parametric oscillator having excellent beam quality.